Screw dispenser

For MPN determination, sterile pipettes calibrated in 0.1-ml increments are used. Other equipment includes sterile screw-top dilution bottles containing 99 ml of water and a rack containing six sets of five lactose broth fermentation tubes. A sterile pipette is used to transfer 1.0-ml portions of the sample into each of five fermentation tubes. This is followed by dispensing 0.1 ml into a second set of five. For the next higher dilution (the third), only 0.01 ml of sample water is required. This small quantity is very difficult to pipette accurately, so 1.0 ml of sample is placed in a dilution bottle containing 99 ml of sterile water and mixed. The 1.0-ml portions containing 0.01 ml of the surface water sample are then pipetted into the third set of five tubes. The fourth set receives 0.1 ml from this same dilution bottle. The process is then carried one more step by transferring 1.0 ml from the first dilution bottle into 99 ml of water in the second for another hundredfold dilution. Portions from this dilution bottle are pipetted into the fifth and sixth tube sets. After incubation (48 h at 35 C), the tubes are examined for gas production and the number of positive reactions for each of the serial dilutions is recorded. 

The organism is L. casei ATCC No. 7469. The basal medium (J6) has been modified it contains twice the concentration listed in Table 10a, and is stable when stored in an amber bottle in the cold. It is kept free from contamination with a volatile preservative. L. casei was maintained in medium given in Table 10b 10 ml of this medium is dispensed into screw-capped tubes and autoclaved for 30 minutes at 118°, 16 psi. It should be transferred every 2 weeks one drop of an 18-hour culture into 10 ml of maintenance medium suffices with subsequent 18-hour incubation at 37°. Cultures should be stored at 4°. 

Bottle-top dispensers, often called Repipets , are quite popular. These are devices that fit on the top of reagent bottles threaded to receive screw caps. The dispensers themselves have screw caps that screw onto the bottles. The caps, however, are fitted with a hand pump with a plunger that draws liquid from the bottle in the upstroke and then dispenses a calibrated volume on the downstroke through a glass tip. Such devices are convenient and help prevent contamination of the reagent from the various pipets that the analyst might use for a transfer. 

For qualitative determination of gelation ability, 3 ml aliquots of the WPC dispersions were dispensed In screw capped test tubes and heated In an oil bath at lOO C. Tubes were removed from the bath at 30-s Intervals and placed Into an Ice bath. Gel strength was evaluated on a visual rating scale of 0 to 5,0 (13, 1 ), The time required at lOO C for the formation of a gel with a rating of 4.0 or higher was reported as gel time. 

The prepared medium is dispensed into screw cap bottles (prescription ovals 125 ml to 250 ml capacity), which should never be filled more than two-thirds full. Bottles of the freshly prepared medium are capped loosely and sterilized in an autoclave or pressure cooker for 15 minutes at 15 pounds pressure (120°C). When the medium has been sterilized and cooled the caps should be tightened upon removal from the autoclave or pressure cooker, and stored in a cool place. 

TECAN introduced the CombiTech Synthesizer in 1996. Recently it was announced [24] that support for this product, including sales, service, and distribution, will be integrated into Perkin-Elmer s global structure. The instrument is based on TECAN s Genesis liquid-handler platform. One of the major advantages of this instrument over other robotic devices is its ability to use, simultaneously, four robotic arms for dispensing. Another four robotic arms are used for aspiration and removal of the reactants and wash solvents to waste. The Teflon reaction block has 48 threaded glass round-bottom reaction vessels (10 mL each). They are screwed onto the block. 

The container must be sealed by a closure. If air is allowed to enter and interact with the essential oil, the chemical reaction of oxidation can occur. Oxidation in this case can be considered the addition of oxygen to an oil constituent to form a new compound. New compounds formed will alter the composition of the oil. Water vapour may also enter from the air. An open or incompletely sealed container will allow essential oil components to escape as vapours, and this will change the balance of constituents. The best choice of closure for a bottle is a screw cap fitted with a wad or washer. Ideally bottles are fitted with childproof tops and drop dispensers to control amounts dispensed. 

The sticker liquid, which is in the tank shown below the forward edge of the wing, is metered into a mixing chamber located immediately below the funnel-like structure located behind the tank. A wind-driven propeller mixes the sticker and the flake, which originates in the funnel structure, and forces the mixture out of the chamber via a screw-type arrangement toward a terminus equipped with a blade-like arrangement that rotates rapidly in flight. With the aid of the slip stream, the blade dispenses the flakes as individual particles. 

Liquid-based oral drug products are usually dispensed in glass bottles (sometimes in plastic), often with a screw cap with a liner, and possibly with a tamper-resistant seal or an overcap that is welded onto the bottle. The same cap liners and inner seals are sometimes used with solid oral dosage forms. A laminated material can be used to overwrap glass bottles for extra safety. 

A number of topical products marketed as a pressurized aerosol may be dispensed in a metallic bottle with a screw cap. Topical dosage forms in aluminum tubes usually include a liner. A tube liner is frequently a lacquer or shellac whose composition should be stated. A metallic pressurized packaging system for a liquid-... 

Caution Benzoyl peroxide is flammable and may explode on heating or on impact. There is no need for more than a gram or two in the laboratory at any one time. It should be stored in and dispensed from waxed paper containers and not in metal or glass containers with screw-cap lids. 

Label the required number of 1.5-mL screw-cap tubes and dispense 900 pL of lysis buffer to each of them. 

Proprietary source containers are also used in the FlexiWeigh system (Mettler Toledo). Dispensing is effected using either tapping or by the built-in Archimedes screw. According to the manufacturer s specifications, even small amounts such as 1 mg can be dispensed with an accuracy of 0.2 mg. 

All-purpose cleaners, as powders, were dispensed from boxes or bags. This could be a messy operation, and spills are difficult to clean up. Liquid all-purpose cleaners are dispensed from bottles, usually equipped with screw off or flip-top caps. Therefore, these were not only less messy to dispense, but they were easier to close tightly to eliminate spills. The caps could also be used to measure the product... 

A closure may serve additional purposes to its prime objective of product retention. Dispensing closures offer pouring aids, facilities for providing drops, sprays, or a measured (metered) dose. Perhaps one of the earliest dispensing uses was the dropperpipette which locked into a retaining hole in a conventional screw cap. This is still used today, with the bulb made from either natural or synthetic rubber or silicone elastomer, and a pipette of either glass or thermoplastic material. 

Nowadays the smaller sizes of round and rectangular section containers for liquids are often fitted with plastic dispensing closures. It is also possible to produce two-piece screw top containers in aluminium in a similar manner to that in which two-piece aluminium aerosol cans are produced. In this case the base, which may be either flat or domed, is invariably constructed in aluminium so that the resultant container may be used for corrosive chemicals without further internal treatment. 

ESI-MS Process Evaluation Setup. The chip glued onto the metal holder depicted in Figure 9.3d was screwed on the Nanospray interface of the mass spectrometer. Cone gas (automatically controlled via the ESI-MS software) was set at a value of 260Lh 1. Nebulizing argon gas was dispensed at various pressures up to about 8 bar. 

There are a variety of drive mechanisms commonly used automated dispensing including cable drive, lead screw, and linear motors. Most modern equipment uses closed loop servo mechanisms, although open loop stepper motors can be found in some less expensive equipment. The drive mechanism is not as important as the overall speed and accuracy of the equipment. Other factors, such as the alignment process and dispensing technology often overshadow the characteristics of the drive mechanism. 

Culture tubes (13 by 100 mm) with Teflon-lined screw caps are filled approximately three-fourths full with G-12 mesh anhydrous silica gel (Davison Chemical Co., Baltimore, Md.), dry sterilized at 400°F for 1% hr. The tubes are then marked with the mutant numbers of the strains to be put into stock and the tubes are chilled and kept in an ice bath. About 2.5 ml of (Carnation instant) nonfat dry milk (7.5 g/100 ml dispensed 2.5 ml/tube in 13 by 100 mm test tubes and autoclaved for 10 min) is added to a 5- to 7-day-old culture (in a 13 by 100 mm test tube). The conidia are then suspended by placing the tube on a vortex mixer, and 1 ml of the resulting conidial suspension is added to the cold silica gel tube. This tube is stored at ice-water temperature until all culture tubes have been put into stock. (Silica gel heats up when the milk is added and the precooling prevents a rise in temperature which could otherwise cause inactivation of some of the conidia.) All stock tubes are then stored at room temperature for 7 days with the screw caps on loosely. After this period, the caps are tightened and the tubes are shaken to loosen and thoroughly mix the crystals. 

The need to control the feed rate of bulk materials is very common throughout industry. The use of screw feeders to dispense powders, granules, pastes, and other particulate forms of products is prolific. Foods, pharmaceuticals, plastics, pigments, minerals, chemicals, sewage, and a host of diverse industries and products are served by screw feeding equipment. While most applications work at ambient temperature and... 

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